The Internet is a global public network of interconnected computer networks that utilize a standard set of communication and configuration protocols. It consists of many private, public, business, school, and government networks. Within each of the different networks are numerous host devices such as workstations, servers, cellular phones, portable computer devices, to name a few examples. These host devices are able to connect to devices within their own network or to other devices within different networks through communication devices such as hubs, switches, routers, and firewalls, to list a few examples.
The growing problems associated with security exploits within the architecture of the Internet are of significant concern to network providers. Networks and network devices are increasingly affected by the damages caused by Denial of Service (“DoS”) attacks. A DoS attack is defined as an action taken upon on a computer network or system by an offensive external device that prevents any part of the network from functioning in accordance with its intended purpose. This attack may cause a loss of service to the users of the network and its network devices. For example, the loss of network services may be achieved by flooding the system to prevent the normal servicing for performing legitimate requests. The flooding may consume all of the available bandwidth of the targeted network or it may exhaust the computational resources of the targeted system.
Networks that communicate using the Internet Protocol (IP) are an effective and flexible mechanism for enabling a wide variety of applications. However different applications frequently exhibit very different performance and capacity capabilities and place different loads on the underlying IP network. In addition, users place performance requirements (e.g., throughput and responsiveness) on these applications that challenge the queuing and routing techniques employed by IP networks to manage the flow of application traffic.
Current network management tools cannot provide effective techniques for the monitoring and analysis of suspicious traffic across IP networks. Existing techniques focus on individual hosts. These techniques are typically too low-level to provide network management staff with an effective understanding of how hosts ports/services are related to each other. This is because the traffic for a single application can contain numerous distinct IP flows and even larger numbers of IP packets. Current tools present unusual volumes of traffic as separate lists, but they paint an incomplete picture.
What is needed is a technique for monitoring and analyzing packet traffic on IP networks to provide a better understanding of the nature of traffic flowing in and out of the network being monitored.